Diseases, Conditions, Syndromes

How exactly do we spread droplets as we talk? Engineers found out.

For the first time, researchers have directly visualized how speaking produces and expels droplets of saliva into the air. The smallest droplets can be inhaled by other people and are a primary way that respiratory infections ...

Neuroscience

Are your gums saying something about your dementia risk?

Gum disease, especially the kind that is irreversible and causes tooth loss, may be associated with mild cognitive impairment and dementia 20 years later, according to a study published in the July 29, 2020, online issue ...

Health

Is seltzer water healthy?

My health conscious friends and colleagues tell me that they need an alternative to soda but plain water is too boring. They, like many people, are turning to sparkling water and flavored seltzer water.

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Tooth

Teeth (singular tooth) are small whitish structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, and chew food. Some animals, particularly carnivores, also use teeth for hunting or defense. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of tissues of varying density and hardness.

Teeth are among the most distinctive (and long-lasting) features of mammal species. Paleontologists use teeth to identify fossil species and determine their relationships. The shape of the animal's teeth are related to its diet. For example, plant matter is hard to digest, so herbivores have many molars for chewing. Carnivores, on the other hand, need canines to kill prey and to tear meat.

Mammals are diphyodont, meaning that they develop two sets of teeth. In humans, the first set (the "baby," "milk," "primary" or "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful.

Some animals develop only one set of teeth (monophyodont) while others develop many sets (polyphyodont). Sharks, for example, grow a new set of teeth every two weeks to replace worn teeth. Rodent incisors grow and wear away continually through gnawing, maintaining relatively constant length. Many rodents such as voles (but not mice) and guinea pigs, as well as rabbits, have continuously growing molars in addition to incisors.

This text uses material from Wikipedia, licensed under CC BY-SA